Improvement in the preparation of mica



Letters Patent No. 10%,416, dated November 22, 1870.

IMPROVEMENT IN THE PREPARATION OF MICA.

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To all whom it hwy concern":

Be it known that we, Hussy M. J onss'ros and FREDERICK Bscx, both of thecity, county, and State of New York, have invented a new and improvedProcess of Preparing Mica. for use in the arts; and we do hereby declarethat the following is a full, clear, and exact description thereof.

- We take mice. and place it in a furnace or other suitable appliance,and subject it to the action of intense heat for a period varying fromabout ten minutes to an hour or more, according to the degree of heatand the quality of mica. used. We prefer to use it white heat to that ofa. lower temperature. After about tenminutes exposure to the h eet, themica is found to have pattdhiithfitddiiinrip'iii-eiidffiifi'd tb have'uire 'ver a or i refiectiv 'ijualit-y; a more pro nged action of thebeat imparts a beautiful pearly luster, which changes under a furtherexposure to a milk-like quality of color. .As these chauges'takeplace-the mica is found to gradually increase in thickness, and afterreaching the milky color, the laminae, of which it is composed, willhave lost their adhesion to such a degree as tobe easily separated bypressurebetween the fingers, in which condition we reduce it to scales,by forcing through sieves of different sizes, or byeny other suitablemeans.

The mica scales so produced. can be stained 'of any desired color by theuse of suitable dyes, and then be used in place of bronze powders. I

By the use of our invention we are further enabled to prepay sheets ofmica that can be used instead of metal his 3 m many ornament-a pur- WWWe axemvare that mica has been prepared by re-. -duoing it to smallpieces in a stamplngmfl], digesting \vltb'chiorhydric acid, and cleansedby washing, all of which we disclaim; but

Haviug described our invention, l What we claim as new,.and desiuc tosecure by Letters Patent, ls-' I. The process herein described forpreparing mica in sheets or due scales. t

-2. Mica in sheets or line scales, prepared substantially as described.

HENRY M. JOHNSTON. FRED. BECK. Witnesses:

J; H. Lures,

A. B. TERRY.

